A robotic device, such as a legged robot, may have a hydraulic drive system which, in operation, supplies pressurized hydraulic fluid to hydraulic actuators on the robotic device. For instance, the robotic device may have robotic arms and/or legs driven by linear hydraulic actuators (e.g., hydraulic piston-cylinder assemblies). Pressurized hydraulic fluid may cause the linear hydraulic actuators to actuate and thereby move the robotic arms and/or legs. An example legged robot may have one or more hydraulic actuators on each leg (e.g., hip, knee, and ankle actuators). A pump of the hydraulic drive system may pressurize hydraulic fluid. The hydraulic drive system may supply the pressurized hydraulic fluid to the hydraulic actuators on each leg.